Esotropia

• Esotropia


  A type of strabismus where the eyes turn inward
• Classification of esotropia of nonparalytic origin


  • Primary
  • Consecutive
  • Secondary (sensory)
  • Residual
• Primary esotropia


  Esotropia that remains after refractive errors have been corrected and optimum visual acuity reached
• Types of primary esotropia

  • Accommodative
  • Nonaccommodative
• Types of accommodative esotropia

  • Intermittent
  • Constant
• Accommodative esotropia


  Esotropia that can result from an uncorrected hypermetropic refractive error, a high accommodative convergence to accommodation ratio (AC/A ratio) or a combination of the two
• Accommodative esotropia


  • The magnitude of the hypermetropia determines the resulting accommodative convergence
  • The patient's need for clear vision determines whether they tolerate blurred vision or diplopia
  • The magnitude of the AC/A ratio determines the level of accommodative convergence for near
• Fully accommodative esotropia


  An esotropia that occurs when accommodation is exerted to overcome uncorrected hypermetropia
• Fully accommodative esotropia


  • Onset commonly in children aged 2 to 5 years
  • Associated with a degree of uncorrected hypermetropia, commonly 2.00-7.00 diopter sphere (DS)
  • Intermittent esotropia that may become constant if left untreated
  • Bifoveal binocular single vision with the hypermetropia corrected, present in most cases
• Management of fully accommodative esotropia


  1. Correction of the refractive error

  2. Restoration of visual acuity

  3. Orthoptic treatment

  4. Surgical treatment
• Convergence excess esotropia


  An esotropia present for near when using an accommodative target, after correction of the refractive error
• Partially accommodative esotropia


  Esotropia with undercorrected hypermetropia
• Convergence spasm


  A condition with other features like pupillary miosis and accommodative spasm, in addition to esotropia
• Orthoptic treatment for fully accommodative esotropia


  • Aims to overcome suppression, gain recognition of diplopia, achieve voluntary control of the esotropia without spectacles, and improve the controlled binocular acuity without spectacles
  • Factors to consider include degree of hypermetropia, patient age and cooperation, and size of deviation without spectacles
• Stages of orthoptic treatment

  1. Diplopia recognition

  2. Control of esotropia

  3. Improvement of the controlled binocular acuity without the correction
• Convergence excess accommodative esotropia


  An esotropia that occurs on near fixation with the refractive error corrected, due to the excessive accommodative convergence exerted for each dioptre of accommodation
• Convergence excess accommodative esotropia

  • Onset commonly in the age range 2-5 years
  • Patients have a high AC/A ratio, often exceeding 8:1
  • Uncorrected hypermetropia is common, often 1.50 to 5.00 DS
  • Intermittent esotropia to an accommodative target for near, becoming more constant with time
• Convergence excess esotropia


  • Onset commonly in the age range 2-5 years
  • All patients have a high AC/A ratio, often exceeding 8:1
  • Uncorrected hypermetropia is common and esotropia is often present in the distance as well as for near until the hypermetropia has been corrected
  • An intermittent esotropia to an accommodative target for near, becoming more constant with time
  • An esotropia first noticed when the child looks up from a book, or when eating
  • Equal VA
  • Microtropia, which is more commonly seen in this group compared with its incidence in fully accommodative esotropia
  • Suppression is present in most patients when the deviation is manifest
  • A normal near point of accommodation
• Accommodative convergence to accommodation ratio (AC/A ratio) measurement

  1. Gradient method

  2. May change following a period of monocular occlusion
• Prism adaptation test


  1. Beneficial effect on surgical outcomes of patients with acquired esotropia

  2. Used in convergence excess esotropia, with the best surgical outcome obtained from those prism adapted for their near angle
• Differential diagnosis


  • Fully accommodative esotropia with undercorrected hypermetropia
  • V-pattern esotropia
  • Near esotropia (nonaccommodative convergence excess)
  • Hypoaccommodative convergence excess
  • Partially accommodative esotropia with a high AC/A ratio
• Correction of refractive error

  1. Hypermetropia should be fully corrected

  2. If myopia is present, the decision to correct or undercorrect depends on the planned treatment for the strabismus
• Restoration of visual acuity


  1. Amblyopia should be managed

  2. Microtropia usually results in an optimum VA of 0.2 (6/9.5) in the affected eye
• Factors governing choice of treatment


  • Size of the deviation for both near and distance fixation
  • Size of the AC/A ratio
  • Level of BSV
  • Difference of opinion in the United States and Europe on the relative value of bifocal spectacles and surgery
• Bifocal spectacles


  1. Aim is to provide the patient with a reading correction of sufficient strength to enable him or her to maintain comfortable BSV for all near activities, with an adequate CBA

  2. Bifocals are used as the primary treatment until the patient is around 6 to 8 years of age

  3. Bifocals can also be useful in myopic patients, to maintain BSV preoperatively, in conjunction with orthoptic treatment, and in the postoperative management of residual deviations
• Bifocals discarded


  • Convergence excess remains compensated
  • Gradual reduction in bifocals
  • Bifocals poorly tolerated or not compensated, surgical treatment
• Contact lenses are not in widespread clinical use and others have not found them to be effective
• Botulinum toxin has not been effective as a primary form of treatment for this type of esotropia, but is recommended as an important option in the management of surgical overcorrection
• Surgical treatment


  • Preferred after the age of 6 years
  • Aims to reduce the near deviation to allow fusion for both near and distance fixation with any refractive error fully corrected
  • Amount of surgery is calculated based on the response to prism adaptation testing at near
• Surgical options


  • Weakening procedure to both medial rectus muscles
  • Conventional recession
  • Supramaximal recession with or without a hang-back suture
  • Combining recession with a posterior fixation suture (PFS)
  • Single medial rectus muscle recession is not effective
  • Bilateral medial rectus muscle recession of less than 4 mm is ineffective
  • Medial rectus recession followed by a PFS or enhanced hang-back recession performed as a two-stage procedure
• Two groups identified following prism adaptation

  • Group 1: An esophoria ≤8 A is present for near and distance
  • Group 2: An esophoria ≤8 A is present for near and an exotropia at distance
• Bilateral medial rectus muscle recession of less than 4 mm


  Similarly ineffective
• Medial rectus recession followed by a PFS or enhanced hang-back recession

  1. Performed as a two-stage procedure

  2. Has a smaller effect on the deviation than carrying out the two procedures at one sitting
• Patients, especially older children, should be warned about the likelihood of crossed diplopia on lateral gaze in the immediate postoperative period, particularly if supramaximal hang-back recessions or recessions with PFS are used
• With both these techniques the variable limitation of adduction postoperatively causes incomitance on lateral gaze, which may persist
• Two groups can be identified following prism adaptation

  • Group 1: An esophoria ≤8 A is present for near and distance
  • Group 2: An esophoria ≤8 A is present for near and an exotropia at distance
• The PFS augments the effect of medial rectus recession; therefore the amount of surgery is reduced to avoid overcorrection
• Reoperation may be required for patients with surgical undercorrection or overcorrection when the residual deviation has failed to respond to nonsurgical measures
• Leitch et al. (1990) reported a reoperation rate of as high as 16%
• Residual esotropia


  • Residual near angles of less than 20 A may respond to bifocals and orthoptic treatment
  • Residual near angles between 20 and 30 A. If further surgery is still an option, we prefer reoperation to other forms of treatment. Failing this, these patients may benefit from bifocal use with planned reduction in reading addition around 9-10 years of age
  • Residual near angles greater than 30 A will require either further surgery or long-term bifocals. Alternatively, the patient can be electively left without further treatment if symptom free